Open ocean food web connectivity: Insights from combined perspectives

Wednesday — June 19, 2013
Pacific Forum — 3:00 p.m.

The structure and function of open ocean food webs can vary widely in both the horizontal and vertical dimensions. Oligotrophic subtropical gyre waters support diverse communities of pelagic animals, which are distributed throughout the epi-, meso-, and bathypelagic layers of the ocean. This presentation will evaluate the trophic linkages between animals that inhabit these different depth layers, ultimately connecting surface and deep ocean waters through feeding and diel vertical migration. Of particular importance is defining the ecological roles of large mid-trophic level mesopelagic fishes (e.g., lancetfish, escolar, snake mackerel, opah), which have rapidly increased in abundance in the North Pacific Subtropical Gyre (NPSG) for unknown reasons. Pelagic food web insights will be presented based on a unique combination of conventional methods (stomach content analysis, stable isotopes) alongside novel biochemical techniques (compound specific isotope analysis of amino acids, trace metals, and fatty acids).